Imprint lithography has been used to fabricate semiconductor devices as well as for electrical, optical, photonic and biological applications.
Specific to the present disclosure, Si-based MEMS dispensers represent a potential advancement to existing imprint lithography and other processes, as they may be adapted to dispense higher dot-per-inch (“dpi”) resist drop patterns which may in turn improve process throughput and reduce defects. However, resists for semiconductor applications are often designed to spread quickly over Si substrates. This arrangement creates potential defect issues for Si-based MEMS dispensers, as the resist can also spread across the surface of the printhead and form a continuous film. If this film grows thick and/or quickly enough, it can lead to imprint resist leaking onto the substrate, thus compromising the entire substrate and devices formed thereon. Furthermore, a build-up of such fluid layers on the printhead surface can compromise nozzle performance leading to drop volume and placement inaccuracy, which in turn leads to imprint patterning defects, or even to nozzles being blocked, causing non-fill pattern defects. While blotting the fluid film may be one way of correcting the defect, it may further lead to additional compromises, including the introduction of unacceptable levels of particle contamination.
In addition, typical anti-wetting coatings deteriorate rapidly when exposed to the environment, leading to diminished surface contact angles, which in turn make the coatings unsuitable for microfluid application. Although hydrolysis has been held to blame for the rapid deterioration, other factors may be contributing and/or enabling the hydrolysis.
One approach to limiting these defect issues includes applying a hydrophobic anti-wetting coating to the printhead faceplate, thus lessening fluid spreading and build-up.
Various methods for applying an anti-wetting layer for Si surfaces exist; however, these methods do not translate well for MEMS applications in e.g. imprint lithography, leaving breaches in the technology, including a need for a more stable, longer lasting anti-wetting coating.
Accordingly, it would be particularly beneficial to disclose apparatus and methods for preparing and applying an anti-wetting coating to a MEMS device without existing detriments.